1. Field of the Invention
The present invention relates to a vehicle headlamp comprising a reflector configured to forward reflect the light from a segment light source extending in a vehicle width direction such that a light distribution pattern is formed that has a cut-off line at an upper end thereof.
Background Art
2. Related Art
Conventionally, as a vehicle headlamp, headlamps having reflectors that forward reflect the light from a segment light source extending in a vehicle width direction such that a light distribution pattern is formed that has a cut-off line at an upper end thereof are known.
In typical cases, a vehicle headlamp is configured to split the reflecting surface of a reflector into a plurality of reflection regions. Each of the reflection regions is configured with a predetermined curved surface. The predetermined curved surfaces are formed with a paraboloid of revolution that uses the middle position of the segment light source in right and left directions as a focal point formed as a reference plane such that a light distribution pattern is formed that has a cut-off line at an upper end thereof is described in “Patent Document 1.”
Further, as described in “Patent Document 2,” a vehicle headlamp has been configured to arrange a segment light source in a first focal point of an ellipsoid of revolution in a first reflector that has a reflecting surface including the ellipsoid of revolution, and arrange a shade in a second focal point of the ellipsoid of revolution. Thus, a portion of the light from the segment light source reflected by the first reflector is shielded by means of the shade and the shielded light is forward reflected by means of a second reflector such that a light distribution pattern is formed that has a cut-off line at an upper end thereof.
Patent Document 1: JP-A-09-022607
Patent Document 2: JP-A-2000-276916
By configuring the reflector of a vehicle headlamp to forward reflect the light from the segment light source extending in the vehicle width direction as described above, it is possible to enhance the use efficiency of luminous fluxes even if the right-and-left width of the reflector is narrow.
However, the vehicle headlamp described in the above “Patent Document 1” has problems in that it is not easy to clearly form an oblique cut-off line that rises obliquely with respect to the horizontal direction because the reflecting surface of the reflector is constituted with a curved surface that is formed with a paraboloid of revolution that uses the middle position of the segment light source in the right and left directions as a focal point formed as a reference plane.
On the other hand, the vehicle headlamp described in the above “Patent Document 2” has problems in that it is possible to clearly form an oblique cut-off line, but it is not easy to make the luminous intensity distribution of a light distribution pattern just below the oblique cut-off line as desired because the cut-off line is formed as an inverted projection image of the shade.